Broadband Nonreciprocal Phase Shifter Design Technique

Abstract

In this contribution, a novel method to design broadband nonreciprocal phase shifters (NRPS) is illustrated: this new topology is based on the combination of two directive-distributed amplifiers with a four-port phase-shifting network. The presented approach includes explicit design formulae allowing for arbitrary differential-phase implementation. Extensive design description of a 180° NRPS, acting as broadband differential-phase inverter, is also provided. The $3.5 \times 3.4$ mm2 demonstrator, realized in 0.5 $\mu \text{m}$ GaN HEMT technology, has an average zero insertion loss up to 25 dBm of input power, 180° ± 2° differential-phase shift, and good port matching over the 3–7-GHz operating bandwidth.